257672809 has 2 divisors, whose sum is σ = 257672810. Its totient is φ = 257672808.

The previous prime is 257672797. The next prime is 257672819. The reversal of 257672809 is 908276752.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 192515625 + 65157184 = 13875^2 + 8072^2 .

It is a cyclic number.

It is not a de Polignac number, because 257672809 - 2⁵ = 257672777 is a prime.

It is not a weakly prime, because it can be changed into another prime (257672819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128836404 + 128836405.

It is an arithmetic number, because the mean of its divisors is an integer number (128836405).

Almost surely, 2^257672809 is an apocalyptic number.

It is an amenable number.

257672809 is a deficient number, since it is larger than the sum of its proper divisors (1).

257672809 is an equidigital number, since it uses as much as digits as its factorization.

257672809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 423360, while the sum is 46.

The square root of 257672809 is about 16052.1901620931. The cubic root of 257672809 is about 636.3404498534.

The spelling of 257672809 in words is "two hundred fifty-seven million, six hundred seventy-two thousand, eight hundred nine".